Invermere
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Invermere clear sky chart from 2005-11-06 to 2025-02-25.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	4 7% 3 9% 6% 6% 6% 5% 8% 9% 36%	112174
	Night	3 8% 4 11% 7% 6% 6% 5% 7% 9% 33%	115126
Transparency	Day	40% 16% 19% 17% 7% 1	111932
	Night	40% 16% 20% 17% 6% 1	115014
Seeing	Day	10% 17% 34% 27% 10% 2	15449
	Night	6% 9% 43% 31% 10% 1	24705

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	1 9% 6% 20% 12% 10% 10% 6% 7% 6% 13%	3179
	11th to 20th	Day	1 6% 4 11% 9% 8% 6% 5% 7% 9% 34%	3543
	21st to end	Day	2 11% 7% 15% 7% 5% 6% 5% 7% 7% 29%	4004
February	1st to 10th	Day	1 8% 4 11% 10% 8% 8% 7% 11% 10% 23%	1600
	11th to 20th	Day	1 7% 4 11% 8% 8% 8% 6% 11% 11% 26%	1733
	21st to end	Day	1 8% 3 11% 11% 9% 8% 7% 9% 9% 24%	1611
March	1st to 10th	Day	1 5% 4 9% 7% 6% 8% 7% 11% 12% 30%	3138
	11th to 20th	Day	1 5% 3 9% 7% 7% 8% 7% 8% 9% 37%	3334
	21st to end	Day	3 12% 5% 10% 7% 7% 7% 7% 8% 9% 24%	4032
April	1st to 10th	Day	5% 12% 4 10% 8% 7% 6% 5% 9% 9% 26%	2280
	11th to 20th	Day	5% 12% 4 10% 6% 6% 6% 5% 9% 9% 29%	2411
	21st to end	Day	7% 11% 4 10% 7% 7% 6% 5% 7% 8% 28%	2470
May	1st to 10th	Day	10% 13% 5% 8% 6% 6% 6% 4 6% 7% 27%	4385
	11th to 20th	Day	6% 9% 3 9% 7% 6% 7% 6% 8% 9% 29%	4552
	21st to end	Day	12% 10% 4 11% 7% 6% 7% 5% 7% 8% 24%	5161
June	1st to 10th	Day	14% 10% 4 8% 6% 5% 5% 5% 6% 7% 30%	2850
	11th to 20th	Day	13% 9% 3 9% 7% 6% 6% 5% 7% 8% 28%	2850
	21st to end	Day	8% 5% 2 6% 5% 6% 7% 6% 8% 8% 40%	2850
July	1st to 10th	Day	4 4 2 5% 3 4 4 4 6% 7% 57%	4740
	11th to 20th	Day	3 2 1 3 3 3 4 4 7% 8% 61%	4717
	21st to end	Day	2 2 1 4 4 4 5% 4 7% 9% 58%	4790
August	1st to 10th	Day	3 3 2 6% 4 4 6% 5% 8% 9% 50%	4401
	11th to 20th	Day	5% 4 2 5% 4 4 6% 5% 8% 10% 47%	4178
	21st to end	Day	5% 4 2 4 4 5% 5% 4 7% 9% 51%	4476
September	1st to 10th	Day	5% 6% 2 5% 4 4 5% 5% 6% 9% 49%	2280
	11th to 20th	Day	7% 6% 2 6% 6% 5% 6% 5% 6% 9% 43%	2141
	21st to end	Day	7% 7% 3 8% 6% 5% 5% 6% 6% 9% 39%	2090
October	1st to 10th	Day	3 5% 2 5% 5% 4 5% 5% 7% 10% 49%	3394
	11th to 20th	Day	2 4 2 6% 4 5% 6% 5% 9% 13% 44%	2842
	21st to end	Day	3 8% 3 8% 6% 7% 6% 5% 7% 10% 37%	3101
November	1st to 10th	Day	3 9% 6% 12% 8% 8% 7% 7% 8% 9% 23%	1761
	11th to 20th	Day	1 6% 4 12% 9% 9% 9% 7% 9% 9% 24%	1450
	21st to end	Day	1 6% 4 14% 11% 9% 7% 7% 11% 11% 18%	1400
December	1st to 10th	Day	2 5% 2 12% 10% 10% 9% 8% 10% 10% 22%	2290
	11th to 20th	Day	1 9% 6% 20% 11% 9% 7% 5% 8% 8% 16%	2642
	21st to end	Day	1 9% 7% 19% 9% 9% 9% 6% 8% 8% 16%	3498
January	1st to 10th	Night	2 11% 7% 23% 11% 9% 8% 5% 6% 6% 12%	6766
	11th to 20th	Night	1 6% 4 12% 9% 8% 8% 6% 9% 11% 28%	6397
	21st to end	Night	2 15% 8% 13% 6% 4 5% 5% 6% 9% 26%	6952
February	1st to 10th	Night	1 11% 5% 14% 9% 9% 8% 6% 9% 8% 18%	2800
	11th to 20th	Night	1 11% 6% 11% 8% 7% 7% 6% 8% 9% 27%	2549
	21st to end	Night	1 9% 4 12% 9% 9% 7% 6% 8% 8% 28%	1937
March	1st to 10th	Night	1 6% 4 9% 6% 6% 7% 7% 8% 10% 36%	3736
	11th to 20th	Night	1 7% 2 7% 6% 5% 6% 7% 8% 9% 42%	3645
	21st to end	Night	4 13% 4 11% 6% 7% 7% 6% 8% 8% 25%	3617
April	1st to 10th	Night	3 12% 3 6% 5% 5% 5% 5% 7% 10% 38%	1900
	11th to 20th	Night	3 10% 3 8% 5% 5% 5% 6% 8% 9% 37%	1720
	21st to end	Night	4 9% 3 7% 5% 5% 6% 5% 6% 10% 39%	1710
May	1st to 10th	Night	8% 12% 4 10% 6% 5% 5% 4 5% 7% 35%	2572
	11th to 20th	Night	5% 6% 2 7% 5% 5% 5% 5% 7% 9% 43%	2338
	21st to end	Night	10% 9% 4 7% 6% 6% 6% 6% 8% 8% 31%	2414
June	1st to 10th	Night	12% 6% 3 6% 4 5% 5% 5% 6% 11% 39%	1330
	11th to 20th	Night	10% 8% 2 7% 6% 5% 5% 6% 8% 8% 34%	1330
	21st to end	Night	6% 4 1 6% 3 3 4 5% 7% 10% 50%	1330
July	1st to 10th	Night	3 3 1 5% 4 4 4 4 5% 7% 60%	2220
	11th to 20th	Night	2 2 1 3 2 3 4 3 6% 9% 65%	2240
	21st to end	Night	2 1 1 3 2 3 3 3 5% 8% 70%	2762
August	1st to 10th	Night	4 4 1 5% 3 4 5% 5% 7% 10% 51%	2529
	11th to 20th	Night	5% 4 2 5% 4 4 5% 4 6% 10% 51%	2654
	21st to end	Night	5% 6% 2 5% 3 2 4 3 6% 8% 56%	3178
September	1st to 10th	Night	6% 3 1 4 3 3 4 4 7% 9% 55%	1900
	11th to 20th	Night	7% 6% 2 6% 4 4 4 4 5% 8% 50%	2038
	21st to end	Night	6% 5% 2 5% 3 5% 5% 4 7% 9% 49%	2090
October	1st to 10th	Night	3 4 2 5% 4 3 4 4 7% 12% 53%	3569
	11th to 20th	Night	3 5% 1 6% 4 4 6% 6% 7% 10% 49%	4086
	21st to end	Night	3 6% 3 9% 6% 6% 6% 6% 8% 11% 36%	4457
November	1st to 10th	Night	5% 11% 5% 10% 6% 6% 6% 7% 9% 9% 25%	2535
	11th to 20th	Night	2 9% 5% 12% 10% 7% 7% 6% 8% 10% 23%	2927
	21st to end	Night	2 10% 5% 17% 10% 8% 8% 5% 8% 9% 17%	3000
December	1st to 10th	Night	2 7% 3 15% 11% 10% 9% 6% 8% 10% 20%	4890
	11th to 20th	Night	9% 5% 22% 12% 10% 8% 6% 7% 7% 14%	5550
	21st to end	Night	2 11% 9% 23% 10% 10% 6% 4 6% 6% 12%	7458

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	56% 21% 14% 7% 1	3179
	11th to 20th	Day	42% 16% 17% 15% 7% 3	3567
	21st to end	Day	38% 21% 24% 13% 3	4004
February	1st to 10th	Day	51% 17% 15% 10% 7% 1	1600
	11th to 20th	Day	47% 19% 17% 12% 4	1741
	21st to end	Day	50% 17% 18% 11% 5%	1611
March	1st to 10th	Day	42% 19% 19% 13% 7%	3138
	11th to 20th	Day	35% 16% 28% 16% 4	3335
	21st to end	Day	50% 21% 17% 9% 3	4032
April	1st to 10th	Day	53% 16% 21% 8% 2	2280
	11th to 20th	Day	49% 15% 19% 14% 2	2411
	21st to end	Day	52% 15% 18% 13% 2	2470
May	1st to 10th	Day	52% 13% 14% 18% 3	4385
	11th to 20th	Day	40% 18% 19% 20% 4	4556
	21st to end	Day	49% 18% 19% 12% 2	5162
June	1st to 10th	Day	52% 10% 15% 15% 6% 1	2850
	11th to 20th	Day	52% 13% 16% 14% 5%	2850
	21st to end	Day	37% 15% 19% 18% 10% 1	2850
July	1st to 10th	Day	25% 8% 13% 24% 26% 4	4666
	11th to 20th	Day	19% 8% 13% 29% 26% 5%	4636
	21st to end	Day	20% 8% 16% 25% 24% 8%	4639
August	1st to 10th	Day	24% 13% 18% 33% 9% 2	4384
	11th to 20th	Day	27% 14% 25% 25% 8% 1	4220
	21st to end	Day	26% 12% 29% 25% 7% 1	4475
September	1st to 10th	Day	31% 10% 21% 26% 11% 2	2280
	11th to 20th	Day	37% 12% 18% 25% 8% 1	2141
	21st to end	Day	40% 13% 20% 19% 7% 1	2090
October	1st to 10th	Day	27% 14% 32% 22% 3	3394
	11th to 20th	Day	29% 19% 28% 19% 5%	2842
	21st to end	Day	38% 18% 25% 16% 3	3101
November	1st to 10th	Day	57% 17% 14% 10% 2	1761
	11th to 20th	Day	52% 17% 18% 10% 3	1450
	21st to end	Day	50% 20% 19% 8% 3	1400
December	1st to 10th	Day	48% 26% 17% 7% 1	2290
	11th to 20th	Day	55% 22% 14% 6% 2	2644
	21st to end	Day	44% 22% 18% 12% 3	3498
January	1st to 10th	Night	59% 21% 12% 7% 1	6766
	11th to 20th	Night	41% 19% 16% 14% 9% 2	6435
	21st to end	Night	42% 20% 21% 13% 3	6952
February	1st to 10th	Night	58% 14% 13% 10% 5%	2800
	11th to 20th	Night	49% 16% 18% 11% 5%	2551
	21st to end	Night	47% 16% 20% 12% 5% 1	1937
March	1st to 10th	Night	35% 19% 26% 15% 6%	3736
	11th to 20th	Night	29% 18% 30% 18% 4	3645
	21st to end	Night	44% 21% 20% 12% 2	3617
April	1st to 10th	Night	38% 17% 26% 14% 5%	1900
	11th to 20th	Night	41% 14% 22% 18% 5% 1	1720
	21st to end	Night	40% 12% 22% 20% 5% 1	1710
May	1st to 10th	Night	47% 11% 17% 20% 5%	2572
	11th to 20th	Night	27% 16% 22% 29% 4	2338
	21st to end	Night	41% 17% 20% 18% 5%	2414
June	1st to 10th	Night	39% 14% 17% 21% 8% 1	1330
	11th to 20th	Night	47% 12% 17% 18% 6%	1330
	21st to end	Night	26% 12% 23% 26% 12% 1	1330
July	1st to 10th	Night	21% 9% 17% 21% 28% 6%	2185
	11th to 20th	Night	17% 5% 13% 33% 26% 5%	2198
	21st to end	Night	13% 7% 14% 29% 27% 10%	2674
August	1st to 10th	Night	21% 14% 20% 32% 10% 2	2521
	11th to 20th	Night	24% 12% 26% 28% 9% 1	2678
	21st to end	Night	24% 9% 33% 25% 8% 1	3178
September	1st to 10th	Night	23% 13% 21% 27% 15% 1	1900
	11th to 20th	Night	32% 10% 19% 28% 10% 1	2038
	21st to end	Night	29% 12% 25% 24% 9%	2090
October	1st to 10th	Night	23% 15% 28% 29% 5%	3569
	11th to 20th	Night	26% 16% 29% 24% 4	4086
	21st to end	Night	34% 21% 24% 19% 2	4457
November	1st to 10th	Night	52% 17% 17% 10% 3	2535
	11th to 20th	Night	53% 15% 17% 10% 4	2927
	21st to end	Night	59% 14% 16% 7% 4	3000
December	1st to 10th	Night	49% 25% 17% 8% 1	4890
	11th to 20th	Night	62% 19% 10% 8% 1	5547
	21st to end	Night	55% 19% 15% 8% 3	7458

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	6% 12% 35% 31% 10% 7%	200
	11th to 20th	Day	3 10% 37% 35% 13% 3	200
	21st to end	Day	3 11% 42% 33% 7% 3	220
February	1st to 10th	Day	5% 18% 47% 21% 8% 2	200
	11th to 20th	Day	3 11% 42% 35% 9% 1	317
	21st to end	Day	7% 17% 41% 28% 7% 1	399
March	1st to 10th	Day	8% 28% 37% 19% 8% 1	460
	11th to 20th	Day	7% 27% 36% 22% 7% 2	460
	21st to end	Day	10% 20% 38% 22% 9% 1	506
April	1st to 10th	Day	13% 24% 36% 21% 6% 1	460
	11th to 20th	Day	12% 25% 31% 23% 8% 1	452
	21st to end	Day	15% 20% 33% 22% 8% 2	460
May	1st to 10th	Day	14% 21% 32% 23% 8% 2	463
	11th to 20th	Day	16% 16% 29% 25% 12% 1	585
	21st to end	Day	17% 15% 28% 28% 11% 1	734
June	1st to 10th	Day	19% 19% 31% 25% 5%	680
	11th to 20th	Day	16% 21% 32% 21% 9% 1	680
	21st to end	Day	10% 14% 32% 30% 13% 1	680
July	1st to 10th	Day	9% 11% 30% 33% 15% 1	671
	11th to 20th	Day	9% 14% 33% 30% 12% 2	658
	21st to end	Day	4 15% 34% 32% 13% 2	531
August	1st to 10th	Day	6% 10% 32% 34% 14% 3	487
	11th to 20th	Day	7% 13% 28% 32% 16% 4	477
	21st to end	Day	9% 16% 30% 29% 12% 3	539
September	1st to 10th	Day	11% 20% 28% 26% 11% 5%	490
	11th to 20th	Day	10% 16% 31% 30% 11% 3	490
	21st to end	Day	14% 22% 34% 22% 7% 1	490
October	1st to 10th	Day	14% 14% 33% 28% 9% 1	485
	11th to 20th	Day	7% 19% 39% 23% 10% 2	300
	21st to end	Day	13% 21% 38% 21% 5% 2	330
November	1st to 10th	Day	6% 17% 42% 26% 8%	300
	11th to 20th	Day	6% 18% 50% 16% 8% 2	225
	21st to end	Day	2 15% 42% 28% 9% 6%	200
December	1st to 10th	Day	4 12% 34% 32% 12% 6%	200
	11th to 20th	Day	3 10% 43% 31% 12% 2	200
	21st to end	Day	2 7% 40% 35% 12% 3	220
January	1st to 10th	Night	5% 12% 48% 26% 7% 1	1000
	11th to 20th	Night	3 8% 48% 32% 7% 2	850
	21st to end	Night	3 7% 51% 31% 6% 1	880
February	1st to 10th	Night	4 9% 49% 29% 8% 1	800
	11th to 20th	Night	6% 7% 51% 27% 9% 1	784
	21st to end	Night	4 9% 45% 32% 10%	646
March	1st to 10th	Night	3 10% 54% 24% 8%	760
	11th to 20th	Night	5% 12% 49% 26% 8% 1	760
	21st to end	Night	6% 9% 47% 29% 9% 1	836
April	1st to 10th	Night	7% 12% 42% 31% 8%	760
	11th to 20th	Night	8% 11% 44% 31% 6%	592
	21st to end	Night	8% 12% 43% 31% 6%	570
May	1st to 10th	Night	10% 9% 39% 32% 9% 1	399
	11th to 20th	Night	7% 9% 34% 41% 10%	374
	21st to end	Night	15% 6% 32% 38% 9%	411
June	1st to 10th	Night	12% 11% 37% 32% 8%	380
	11th to 20th	Night	12% 10% 38% 29% 11%	380
	21st to end	Night	8% 8% 31% 41% 13%	380
July	1st to 10th	Night	5% 4 25% 49% 16%	370
	11th to 20th	Night	4 4 33% 42% 17%	368
	21st to end	Night	2 4 25% 51% 17%	416
August	1st to 10th	Night	5% 3 22% 47% 23% 1	378
	11th to 20th	Night	5% 4 23% 43% 24%	468
	21st to end	Night	6% 9% 26% 40% 18%	646
September	1st to 10th	Night	7% 6% 34% 32% 18% 2	760
	11th to 20th	Night	8% 6% 28% 38% 18% 3	760
	21st to end	Night	10% 9% 37% 33% 10% 1	760
October	1st to 10th	Night	9% 8% 41% 33% 9% 1	760
	11th to 20th	Night	6% 10% 45% 30% 8% 1	760
	21st to end	Night	7% 13% 46% 26% 7% 1	836
November	1st to 10th	Night	9% 11% 49% 23% 7% 1	780
	11th to 20th	Night	7% 17% 47% 23% 5%	981
	21st to end	Night	4 11% 49% 27% 8% 1	1000
December	1st to 10th	Night	6% 10% 47% 27% 10% 1	1000
	11th to 20th	Night	4 8% 48% 30% 10% 1	1000
	21st to end	Night	4 7% 48% 31% 10% 1	1100

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